IPv4 and IPv6

IPv4 :

Internet Protocol version 4 (IPv4) is the fourth revision in the development of the Internet Protocol (IP) and it is the first version of the protocol to be widely deployed. Together with IPv6, it is at the core of standards-based internetworking methods of the Internet. IPv4 is still by far the most widely deployed Internet Layer protocol. As of 2010, IPv6 deployment is still in its infancy.

IPv4 is described in IETF publication RFC 791 (September 1981), replacing an earlier definition (RFC 760, January 1980).

IPv4 is a connectionless protocol for use on packet-switched Link Layer networks (e.g., Ethernet). It operates on a best effort delivery model, in that it does not guarantee delivery, nor does it assure proper sequencing or avoidance of duplicate delivery. These aspects, including data integrity, are addressed by an upper layer transport protocol (e.g., Transmission Control Protocol).

 

IPv6 :

Internet Protocol Version 6 (IPv6) is a version of the Internet Protocol that is designed to succeed Internet Protocol version 4 (IPv4), the first publicly used Internet Protocol in operation since 1981. IPv6 is an Internet Layer protocol for packet-switched internetworking. The main driving force for the redesign of Internet Protocol was the foreseeable IPv4 address exhaustion. IPv6 was developed by the Internet Engineering Task Force (IETF), and is described in Internet standard document RFC 2460, published in December 1998.

IPv6 has a vastly larger address space than IPv4. This results from the use of a 128-bit address, whereas IPv4 uses only 32 bits. The new address space thus supports 2128 (about 3.4×1038) addresses. This expansion provides flexibility in allocating addresses and routing traffic and eliminates the primary need for network address translation (NAT), which gained widespread deployment as an effort to alleviate IPv4 address exhaustion.

IPv6 also implements many other new features. It simplifies aspects of address assignment (stateless address autoconfiguration) and network renumbering (prefix and router announcements) when changing Internet connectivity providers. The IPv6 subnet size has been standardized by fixing the size of the host identifier portion of an address to 64 bits to facilitate an automatic mechanism for forming the host identifier from Link Layer media addressing information (MAC address). Network security is also integrated into the design of the IPv6 architecture, and the IPv6 specification mandates support for IPsec as a fundamental interoperability requirement.

For deployment, IPv6 is largely incompatible with IPv4 at the packet level, and translation services have practical issues that make them controversial.IPv6 and IPv4 are therefore treated as almost entirely separate networks with devices having two separate protocol stacks if they need to access both networks, with tunneling of IPv6 on IPv4 and vice versa. In December 2008, despite marking its 10th anniversary as a Standards Track protocol, IPv6 was only in its infancy in terms of general worldwide deployment. A 2008 study by Google Inc. indicated that penetration was still less than one percent of Internet-enabled hosts in any country. IPv6 has been implemented on all major operating systems in use in commercial, business, and home consumer environments.

IPv4 & IPv6

IPv6 is based on IPv4, it is an evolution of IPv4. So many things that we find with IPv6 are familiar to us. The main differences are: 1.Simplified header format. IPv6 has a fixed length header, which does not include most of the options an IPv4 header can include. Even though the IPv6 header contains two 128 bit addresses (source and destination IP address) the whole header has a fixed length of 40 bytes only. This allows for faster processing. Options are dealt with in extension headers, which are only inserted after the IPv6 header if needed. So for instance if a packet needs to be fragmented, the fragmentation header is inserted after the IPv6 header. The basic set of extension headers is defined in RFC 2460. 2.Address extended to 128 bits. This allows for hierarchical structure of the address space and provides enough addresses for almost every ‘grain of sand’ on the earth. Important for security and new services/devices that will need multiple IP addresses and/or permanent connectivity. 3.A lot of the new IPv6 functionality is built into ICMPv6 such as Neighbor Discovery, Autoconfiguration, Multicast Listener Discovery, Path MTU Discovery. 4.Enhanced Security and QoS Features.Answer:IPv4 means Internet Protocol version 4, whereas IPv6 means Internet Protocol version 6.IPv4 is 32 bits IP address that we use commonly, it can be 192.168.8.1, 10.3.4.5 or other 32 bits IP addresses. IPv4 can support up to 232 addresses, however the 32 bits IPv4 addresses are finishing to be used in near future, so IPv6 is developed as a replacement.IPv6 is 128 bits, can support up to 2128 addresses to fulfill future needs with better security and network related features. Here are some examples of IPv6 address:1050:0:0:0:5:600:300c:326b ff06::c3 0:0:0:0:0:0:192.1.56.10<ins style=”border-style: none; margin: 0px; padding: 0px; visibility: visible; width: 468px; position: relative; height: 60px”></ins> The most important difference is that it has a larger address space. IPv6 uses 128 bits, instead of the 32 bits used in an IPv4 address.
There are also some changes in the header format, and some additional options, like built-in security options. These can be added to IPv4 through additional protocols, so this is really no big deal.

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This article should help you to determine which way to go and which IPv4 – IPv6 combinations to choose.
dual stackThis technique is easy to use and flexible. Hosts can communicate with IPv4 hosts using IPv4 or communicate with IPv6 hosts using IPv6. When everything has been upgraded to IPv6, the IPv4 stack can simply be disabled or removed. Whenever you can, deploying dual-stack hosts and routers offers the greatest flexibility in dealing with islands of IPv4-only applications, equipment, and networks. Dual stack is also the basis for other transition mechanisms. Tunnels need dual-stacked endpoints, and translators need dual-stacked gateways. Disadvantages of this technique include the following: you have two separate protocol stacks running, so you need additional CPU power and memory on the host. All the tables are kept twice: one per protocol stack. A DNS resolver running on a dual-stack host must be capable of resolving both IPv4 and IPv6 address types. Generally, all applications running on the dual-stack host must be capable of determining whether this host is communicating with an IPv4 or IPv6 peer. In a dual-stack network, you need to have a routing protocol that can deal with both protocols (such as IS-IS) or a routing protocol for the IPv4 network (such as OSPFv2) and another routing protocol for the IPv6 network (such as OSPFv3). If you are using dual-stack techniques, make sure that you have firewalls in place that protect not only your IPv4 network, but also your IPv6 network, and remember that you need separate security concepts and firewall rules for each protocol.
tunnelingTunneling allows you to migrate to IPv6 just the way you like. There is no specific upgrade order that needs to be followed. You can even upgrade single hosts or single subnets within your corporate network and connect separated IPv6 clouds through tunnels. You don’t need your ISP to support IPv6 in order to access remote IPv6 networks because you can tunnel through their IPv4 infrastructure. And you don’t need to upgrade your backbone first. As long as your backbone is IPv4, you can use tunnels to transport IPv6 packets over the backbone. If you have an MPLS infrastructure, you have the best foundation for using this to tunnel IPv6 packets as long as you do not want to upgrade the backbone routers to support IPv6 natively.
The disadvantages are known from other tunneling techniques used in the past. Additional load is put on the router. The tunnel entry and exit points need time and CPU power for encapsulating and decapsulating packets. They also represent single points of failure. Troubleshooting gets more complex because you might run into hop count or MTU size issues, as well as fragmentation problems. Management of encapsulated traffic (e.g., per-protocol accounting) is also more difficult due to encapsulation. Tunnels also offer points for security attacks.
nat-ptTranslation should be used only if no other technique is possible and should be viewed as a temporary solution until one of the other techniques can be implemented. The disadvantages are that it does not support the advanced features of IPv6, such as end-to-end security. It poses limitations on the design topology because replies have to come through the same NAT router from which they were sent. The NAT router is a single point of failure, and flexible routing mechanisms cannot be used. All applications that have IP addresses in the payload of the packets will stumble. The advantage of this method is that it allows IPv6 hosts to communicate directly with IPv4 hosts and vice versa. For the reasons mentioned previously, NAT as described in RFC 2765 and RFC 2766 is going to be moved to experimental.
when to choose ipv6?A golden rule says to “never touch a running system.” This rule also applies to your IPv4 networks. As long as they do what you need them to do, let them run. But when an IPv4 network hits the limits for some reason, choose IPv6. IPv6 is mature enough to be used in corporate and commercial networks, as many case studies and deployments worldwide show. High investments in new IPv4 setups, fixes, or complex configurations for IPv4 (especially NATs) should be avoided if possible because they are investments in a technology that will slowly be phased out. When you reach the point where this becomes necessary, evaluate IPv6. Whatever you invest in IPv6 is an investment in future technology. As you can see in the findings of people who present their case studies, getting familiar with the new protocol early, taking some time to play with it before you really need it, and planning for it early saves a lot of cost and headaches.
Here’s the list of indicators that it may be time for you to consider or integrate IPv6:
Your IPv4 network or NAT implementation needs to be fixed or extended.
You are running out of address space.
You want to prepare your network for applications that are based on advanced features of IPv6.
You need end-to-end security for a large number of users and you do not have the address space, or you struggle with a NAT implementation.
Your hardware or applications reach the end of their lifecycle and must be replaced. Make sure you buy products that support IPv6, even if you don’t enable it right away.
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We can see the rapid growth of internet users in last few years and this increase also create challenges for internet management groups, stake holders and service providers. Day by day infrastructure of internet is expanding and we can even enjoy the service of internet in villages and remote areas. Increased of usage also increase online devices. In start internet protocol addressing (a specific IP addressing for each online entity) was designed on 32 bit and this scheme IP version called IPv4.IPv4 addressing is like 203.128.076.001 . decimal is used to make the IPv4 addresses more palatable for humans and a 32-bit address becomes 4 decimal numbers separated by the period (.) character. If we calculate these decimal values and we can get the total number of devices can be participate on this protocol (256x256x256x256) = allows for 4,294,967,296 addresses. It is about 4 billion of addresses and in early days of internet no one can think, 4 billion slot will be full. here we shall discus some disadvantages of IPv4 as we have seen addressing capability problem and after that we shall go through the solution which will replace IPv4 and addressing structure of the new addressing scheme. we shall go through some disadvantages of IPv4 and new features of IPv6.
Rapid Growth of the Internet and the Exhaustion of the IPv4 Addressing
IPv4 allows for 4,294,967,296 addresses which is about 4 billion and IP allocation limits the public IP addresses to a few hundred million. Cause of this limitation companies using NAT (Network Address Translator) to map single public IP to multiple private IP addresses.

IPv4 Security at IP Level
When we communicate at public medium we need to encrypt data to maintain security and privacy. After a passage of time we have now security for IPv4 packets. This security knows as internet protocol security or IPSec but this is an optional for IPv4.

Internet Backbone Maintaining Large Routing Tables
In IPv4 network IDs allocation is very critical and currently more than 87000 routes in the routing tables of internet backbone routers today. The routing infrastructure is based on flat and hierarchical routing.

Quality of Service Concern in IPv4
Now a days internet users are not only limited with browsing and searching data. Current users are well aware of text and voice and video chat and video conferences and online video libraries. This kind of communication need real time data transfer for quality of service. Normally for these kind of services we use UDP (User Data-gram Protocol) or TCP (Transmission Control Protocol).IPv4 TOS field has limited functionality and, over time, has been redefined and locally interpreted. Additionally, payload identification that uses a TCP or UDP port is not possible when the IPv4 packet payload is encrypted.
IPv6
As we can see we have some basic problems in practice of IPv4 now we will check some new features of IPv6. here I like to describe the some of basic features of IPv6. Deployment of IPv6 is a big challenge for internet management groups, stake holders and service providers. It is difficult but not impossible. We can see benefits of IPv6 here. Biggest upgrade jump from IPv4 32 bit to IPv6 128 bit.

IPv6 Header Format
New header is designed to minimize header overhead. by moving both nonessential and optional fields to extension headers that are placed after the IPv6 header. IPv6 header is more efficiently processed at intermediate routers and that generates efficiency. IPv6 is 4 time larger than IPv4 and its header size is twice than older version.

IPv6 Large Addressing Space
In IPv6 source and destination addresses is based on 128 bit. 128 bit addressing can produce over 3.4 x 1038 possible combinations. Currently we can say this is enough but who know about future may be it also face same problem like IPv4 after some decades. 128 bit addressing allow us multiple levels of sub-netting and address allocation. So we can say that we have plenty of address for use in future.

Addressing and Routing Infrastructure Efficiency in IPv6
IPv6 designed to create an efficient, hierarchical, and summarize able routing infrastructure that is based on the common occurrence of multiple levels of Internet Service Providers. It reduce the size of routing table of backbone routers. Which is can cause of efficient internet experience.

Security features is now built-in
IPv6 has been design to support IPsec (AH and ESP header support required) also support mobility version Mobile IPv6. IPSec based on two types of extension headers and a protocol to negotiate security settings. The Authentication header (AH) provides data integrity, data authentication, and replay protection for the entire IPv6 packet. It is better form developers who built-in security features in development of IPv6 rather we bolt on later.

Quality of Service (QoS) of IPv6
As we have already seen about the UDP and TCP protocols for streaming and other multimedia services on internet. Cause the usage of these services are increasing day by day IPv6 have a flow level field in its header which make better and special handling for packets from source to destination. Data traffic is identified in the IPv6 header, support for QoS can be achieved even when the packet payload is encrypted with IPSec and ESP.

IPv4 & IPv6 Disadvantages & Features

We can see the rapid growth of internet users in last few years and this increase also create challenges for internet management groups, stake holders and service providers. Day by day infrastructure of internet is expanding and we can even enjoy the service of internet in villages and remote areas. Increased of usage also increase online devices. In start internet protocol addressing (a specific IP addressing for each online entity) was designed on 32 bit and this scheme IP version called IPv4.IPv4 addressing is like 203.128.076.001 . decimal is used to make the IPv4 addresses more palatable for humans and a 32-bit address becomes 4 decimal numbers separated by the period (.) character. If we calculate these decimal values and we can get the total number of devices can be participate on this protocol (256x256x256x256) = allows for 4,294,967,296 addresses. It is about 4 billion of addresses and in early days of internet no one can think, 4 billion slot will be full. here we shall discus some disadvantages of IPv4 as we have seen addressing capability problem and after that we shall go through the solution which will replace IPv4 and addressing structure of the new addressing scheme. we shall go through some disadvantages of IPv4 and new features of IPv6.

Rapid Growth of the Internet and the Exhaustion of the IPv4 Addressing

IPv4 allows for 4,294,967,296 addresses which is about 4 billion and IP allocation limits the public IP addresses to a few hundred million. Cause of this limitation companies using NAT (Network Address Translator) to map single public IP to multiple private IP addresses.

 

IPv4 Security at IP Level

When we communicate at public medium we need to encrypt data to maintain security and privacy. After a passage of time we have now security for IPv4 packets. This security knows as internet protocol security or IPSec but this is an optional for IPv4.

 

Internet Backbone Maintaining Large Routing Tables

In IPv4 network IDs allocation is very critical and currently more than 87000 routes in the routing tables of internet backbone routers today. The routing infrastructure is based on flat and hierarchical routing.

 

Quality of Service Concern in IPv4

Now a days internet users are not only limited with browsing and searching data. Current users are well aware of text and voice and video chat and video conferences and online video libraries. This kind of communication need real time data transfer for quality of service. Normally for these kind of services we use UDP (User Data-gram Protocol) or TCP (Transmission Control Protocol).IPv4 TOS field has limited functionality and, over time, has been redefined and locally interpreted. Additionally, payload identification that uses a TCP or UDP port is not possible when the IPv4 packet payload is encrypted.

IPv6

As we can see we have some basic problems in practice of IPv4 now we will check some new features of IPv6. here I like to describe the some of basic features of IPv6. Deployment of IPv6 is a big challenge for internet management groups, stake holders and service providers. It is difficult but not impossible. We can see benefits of IPv6 here. Biggest upgrade jump from IPv4 32 bit to IPv6 128 bit.

 

IPv6 Header Format

New header is designed to minimize header overhead. by moving both nonessential and optional fields to extension headers that are placed after the IPv6 header. IPv6 header is more efficiently processed at intermediate routers and that generates efficiency. IPv6 is 4 time larger than IPv4 and its header size is twice than older version.

 

IPv6 Large Addressing Space

In IPv6 source and destination addresses is based on 128 bit. 128 bit addressing can produce over 3.4 x 1038 possible combinations. Currently we can say this is enough but who know about future may be it also face same problem like IPv4 after some decades. 128 bit addressing allow us multiple levels of sub-netting and address allocation. So we can say that we have plenty of address for use in future.

 

Addressing and Routing Infrastructure Efficiency in IPv6

IPv6 designed to create an efficient, hierarchical, and summarize able routing infrastructure that is based on the common occurrence of multiple levels of Internet Service Providers. It reduce the size of routing table of backbone routers. Which is can cause of efficient internet experience.

 

Security features is now built-in

IPv6 has been design to support IPsec (AH and ESP header support required) also support mobility version Mobile IPv6. IPSec based on two types of extension headers and a protocol to negotiate security settings. The Authentication header (AH) provides data integrity, data authentication, and replay protection for the entire IPv6 packet. It is better form developers who built-in security features in development of IPv6 rather we bolt on later.

 

Quality of Service (QoS) of IPv6

As we have already seen about the UDP and TCP protocols for streaming and other multimedia services on internet. Cause the usage of these services are increasing day by day IPv6 have a flow level field in its header which make better and special handling for packets from source to destination. Data traffic is identified in the IPv6 header, support for QoS can be achieved even when the packet payload is encrypted with IPSec and ESP.

 


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